This invention relates to methods of enhancing animal stem cell trafficking, specifically to the use of blue green algae, or a biological component thereof, to enhance the trafficking or homing of such stem cells.
Stem cells are pluripotent cells derived from somatic tissue capable of differentiating into more specialized cells. For example, hematopoietic stem cells can differentiate into many different types of blood cells, including red blood cells, platelets, and leukocytes.
Hematopoietic stem cells are quite abundant and play a role in the continuous lifelong physiological replenishment of blood cells. Stem cells develop into both hematopoietic lineage cells and non-hematopoietic, tissue specific cells. Recently, stem cells have been found to differentiate into a variety of tissue-specific cell types, such as myocytes, hepatocytes, osteocytes, glial cells, and neurons. For example, stem cells have been shown to cross the blood-brain barrier (Willams and Hickey, Curr. Top. Microbiol. Immunol 202:221-245, 1995) and differentiate into neurons (Mezey, Science 290:1779-82, 2000). Thus, it is possible that stem cells could be used to treat Parkinson""s disease (Polli, Haematologica 85:1009-10,2000), Alzheimer""s disease (Mattson, Exp. Gerontol. 35:489-502, 2000), and traumatic brain injury (Magavi, Nature 405: 892-3, 895, 2000). Stem cells also have been shown to differentiate into fibroblast or fibroblast-like cells, and to express collagen (Periera et al., Proc. Natl. Acad. Sci. 95:1142-7, 1998). Thus, it is possible that stem cells can be used to treat osteogenesis imperfecta and bone fractures. Peterson et al. (Science 284:1168-70, 1999) also have shown that liver cells can arise from stem cells. Thus, stem cells may be of use in treating a variety of pathologies of the liver, including, but not limited to cirrhosis. In addition, bone marrow derived stem cells have been demonstrated to migrate to the site of a myocardial infarction and form myocardium (Orlic, Nature 410:701-5, 2000). Thus, stem cells may be use in treating myocardial infarction.
Since stem cells are capable of differentiating into a broad variety of cell types, they play an important role in the healing and regenerative processes of various tissues it and organs. See Koc, O. N., and Lazarus, H. M., Bone Marrow Transplant, 27(3):235-39 (2001). Bone marrow stem cells, including marrow stromal cells (MSCs), injected into a recipient""s circulatory system can integrate into various organs and tissues to become mature, terminally differentiated cells. Therefore, activation and enhancement of stem cell trafficking can amplify these physiological processes and provide a potential therapy for various pathologies.
A method is disclosed herein for enhancing trafficking of stem cells by administering a therapeutically effective amount of blue green algae to a subject. In one embodiment, whole cells of a blue-green algae, or extracts thereof, are administered to the subject to enhance stem cell trafficking. The algae cells may be fresh, dehydrated, or preserved in some manner. In another embodiment, a high-molecular weight polysaccharide fraction of the blue green algae is administered to the subject. Pharmaceutical compositions including a therapeutically effective amount of a blue green algae, or a component thereof, are disclosed herein.
In one embodiment, a therapeutically effective amount of blue-green algae induces a transient increase in the population of some stem cells, such as CD34+ stem cells, in the subject""s circulatory system. The percentage increase in the number of circulating stem cells, compared to a control, is more than about 10%, more than about 25%, more than about 50%, more than about 100%, more than about 200%, more than about 400%, or more than about 500% following administration of the blue green algae. Additionally, administration of certain fractions of whole AFA can increase the homing of stem cells to various parts of the body, evidenced by a decrease in the number of circulating stem cells. For example, administration of a polysaccharide rich fraction of whole AFA increases the homing of CD34+ and NK cells from the circulatory system to various parts of the body.
In some embodiments, the subject provided the blue-green algae is healthy. In other embodiments, the subject suffers a disease or physiological condition.